Hydraulic mechanism



July 28, 1953 I J. F. JOY

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HYDRAULIC 2122222252 12 Sheets-Sheet 11 Filed Jan. 21, 1947- Jul 28,1953 J, F. JOY 2,646,755

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Patented July 28, 1953 HYDRAULIC MECHANISM Joseph F. Joy, Pittsburgh,Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., acorporation of Pennsylvania Application January 21, 1947, Serial No.723,436

'Moreover, single'units of these known types are usually incapable ofoperation selectively either as a pressure generator or as a motorwithout change in parts or additions thereto. .In such pressuregenerators or motors, there is danger, if operated at unusually highspeed, of causing voids in the fluid cavity which reduces theresponsiveness of the hydraulic column, resulting insubstantial powerlosses. Further, in such known mechanisms, when operated at relativelyhigh speeds, there is danger of substantial 'overheating as a result ofthe operation of the mechanism due to lack of adequate cooling means inthe fluid system. Further in s'uchknown mechanisms, flexibility ofoperation and simplicity'of construction and the desired high degree tore-- sponsiveness to controls are lacking, and'due to their relativelycomplicated constructionfare'not only relatively cumbersome and heavybut are also relatively costly to manufacture. Further,

because of the great number of parts heretofore common to suchmechanisms and the high I degree'of accuracy essential to the propercoordination and functioning of so 'many parts in such a mechanism, onlyhighly skilled artisans are permissible for their manufacture, installation, care and operation. By comparison with such known mechanisms, thepresent invention will be found to embody much fewer parts, all

of simple character, and the more important members of which arestandard. products with leading ball and roller bearing manufacturers.

Claims. (01. 103- 161) Another serious weakness of other knownmechanisms which prevents their successful use for" the applicationscontemplated bythe present in-* vention is the greatnumber ofpressure-tight joints that must be maintained leak-tight underconditions of great vibration and shock.- In the present invention, allhigh pressure conduits are internal of the mechanism, whereby absolutesealing becomes unnecessary and theouter en-' closures are only requiredto confine the slight leakages which occur within, and means are pro-'videdifor. returning such leakage back into "the- 2 fluid column formingthe hydraulic medium. It has been common practice with known types ofpressure generators and motors to provide special drain lines connectedbetween the interior or operating cavities of such mechanisms and thesump or reservoir serving the hydraulic system. Inthe present inventionthe improved pressure generator or pump is well adapted for use in highspeed operation and is entirely capable of meeting relatively severedemands of service which call for a usually high degree ofresponsiveness to controls and efiiciency in operation, and is simple inconstruction, relatively light in weight, may be produced at relativelylow cost, and by the provision of interchangeability of component parts,the cost of replacement and repair is relatively low.

It is accordingly a principal object of the present invention to providea hydraulic mechanism which may be operated efficiently at relativelyhigh speeds and which possesses a minimum of weight consistent withgreat durability, high efiiciency, ease of application and operation,and highly responsive to the controls thereof. A further object is toprovide an improved hydraulic mechanism which may be employed as eithera pressure generator or a motor. Another object of the invention is toprovide an improved hydraulic mechanism having improved control meanswhereby displacement may be readily varied. Still another object is toprovide an improved multistage, fluid displacement apparatus havingimproved means for controlling automatically the maximum pressures inthe several stages thereof. A further object is v to provide an improvedhydraulic pressure generator or motor embodying improved cooling meansfor the fluid system. A still further object is to provide an improvedhydraulic mechanism which is relatively simple in design andconstruction and wherein wear due to friction is reduced to a minimum.Another object is to provide a hydraulic mechanism capable of use aseither a pressure generator or fluid motor 1 ject is to provide animproved hydraulic mechanism embodying improved means for the salvagingof all leakage and the return of the same to the intake ports of thehydraulic fluid column, thus completely eliminating the need of externaldrain lines common to such mechanisms. A further object is to provide animproved pressure generator which may have different operatingcharacteristics by a simple change of parts. A still further object isto provide an improved fluid pressure generator which may be operated asa multistage pump, a multi-power or volume pump, or a multi-deliverypump by a simple interchange of parts. Yet another object is to providean improved fluid pressure generator or motor having a novel fluidpassage arrangement and improved valve means for controlling thedistribution of fluid. Still another object is to provide an improvedfluid pressure generator or motor embodying an improved cylinder andpiston structure and an improved cam track against which the pistonsreact. A still further object is. to provide an improved motor drive fora traction wheel. These and other objects of the invention will,however, become more apparent in the course of the following descriptionand as more particularly pointed out in the appended claims.

In-the accompanying drawings there are showri for purposes ofillustration different forms and modifications which the invention mayassume in practice.

In these drawings:

Fig. 1 is a view in central longitudinal vertical section through ahydraulic mechanism constructed in accordance with an illustrative em.-bodiment of the invention.

Fig. 2 is a cross-sectional View taken substantially on line 22 of Fig.l with parts shown in full.

Fig. 3 is a cross-sectional view of another embodiment of the invention,showing means for varying the displacement of the mechanism.

Fig. 4 is a vertical sectional view, with parts shown in full,illustrating manually operable means for controlling the variabledisplacement mechanism disclosed in Fig. 3.

Fig. 5 is a vertical sectional view, with parts shown in full, takensubstantially on line 55 of Fig. 4.

Fig. 6 is a central longitudinal vertical sectional view showing anotherform of the invention arranged for use as a pressure fluid generator.

Fig. 7 is a central longitudinal vertical sectional view of a similarembodiment of the invention which is remotely connected to the pressuregenerator, shown in Fig. 6, to operate as a motor.

Fig. 8 is a central longitudinal vertical sectional view showing themechanisms of Figs. 6 and '7 assembled into a unitary hydraulicmechanism.

Fig. 9 is a plan view illustrating another embodiment of the inventionwhich is provided with a system of controls for regulating the speed anddisplacement.

Fig. 10 is an end elevational view of the mechanism shown in Fig. 9.

Fig. 11 is a cross-sectional view taken substantially on line HH of Fig.9, illustrating the variable displacement pressure generator.

Fig. 12 is a view in central longitudinal vertical section taken throughstill another embodiment of the invention and incorporating means forcooling the hydraulic operating fluid.

Fig. 13 is an elevational view of the mechanism shown in Fig. 12, withparts shown in vertical section to illustrate structural-details.

Fig. 14 is a View in central longitudinal vertical section, illustratinganother embodiment of the invention applied to a traction wheel for thepropulsion thereof.

Fig. '15 is a cross-sectional viewtaken substantially on line I5!5 ofFig. 14.

Fig. 16 is a vertical sectional view similar to Fig. 14, illustratingstill another embodiment of the invention, showing a compound motor forthe propulsion of a traction wheel.

Fig. 17 is a cross-sectional view taken substantially on line l'|-l'l ofFig. 16.

Fig. 18 is an elevational View, with parts shown in section toillustrate structural details, illustrating a multi-stage pressuregenerator constructed in accordance with a further embodiment of theinvention.

Fig. 19 is a vertical sectional view taken substantially on line l3--l9of Fig. 18.

Fig. 20 is a horizontal sectional view taken stantially on line 2)'28 ofFig. 19.

Fig. 21 is a cross-sectional view takensubstantially on line 2l2l ofFig. 20.

Fig. 22 is a plan view of the pintle shown in Fig. 20.

Figs. '23, 24, 25, 26 and 27 are cross-sectional views takenrespectively on lines 2323, 24-44,.

2525, 2E26 and 27-27 of Fig. 22.

Fig. 28 is a view in central longitudinal vertical section taken througha multi-power or volume mechanism constructed in accordance with stillanother embodiment of the invention.

Fig. 29 is a horizontal sectional view taken substantially on line 2929of Fig. 28.

Fig. 30 is a cross-sectional view taken on line 33-35 of Fig. 28.

Fig. 31 is a plan view of the difierent form of pintle shown in Figs.28, 29 and 30.

Figs. 32, 33, 34, 35 and 36 are cross-sectional views taken respectivelyon lines 32.32, 33-33, 3 i3 i, 35-35 and 3G36 of Fig. 31.

Fig. 3'7 is a fragmentary end view of the pintle shown in Fig. 31.

Fig. 38 is a central longitudinal vertical sectional view taken througha multi-delivery hydraulic mechanism constructed in accordance withstill another embodiment of the invention.

Fig. 39 is a horizontal sectional view taken substantially'on line 33-39of Fig. 38.

Fig. 40 is a cross-sectional view taken substantially on line 40-40 ofFig. 38.

Fig. 41 is a plan View illustrating a still different form of pintleshown in Figs. 38, 39 and 40.

Figs. 42, 43, 44, 15 and 46 are cross-sectional views taken respectivelyon lines 412- 32, 53413, 44- 14, 45-45 and 46-46 of Fig. 41.

In Figs. 1 and 2 of the drawings, there is shown a simple embodiment ofthe invention designed for use as a hydraulic pressure generator ormotor. Referring to the drawings, it will be noted that this form ofhydraulic mechanism consists of but five principal parts, namely, acasing I, a cover 2, a stationary shaft or pintle 3, a rotor 4 and a camtrack 5. The rotor 4 is mounted for rotation upon bearings 5 and 1, theformer being supported by the inwardly extending portion of the pintle 3while the latter issupported by the cover 2, thus insuring concentricoperating relation at all times between the pintle 3 and the rotor 4.There is an added provision to secure concentric relation of these partswhich resides in the adjustment afforded by means of a'nut'8 5 threadedwithin the cover part and acting against a seal 9 and through a springthrust rin ID for the. purpose of providing a resilient pre-loading ofthe bearings 6 and T to the extent necessary to maintain axial alinementof the pintle 3 and the rotor 4. This spring ring Ii], due to itsinherent resiliency, serves to compensate for external compression andexpansion due to temperature changes which occur within the hydraulicmechanism during its operation. The adjusting nut 8 may be locked inadjusted position by a seat screw I I, threaded within the cover plateand engaging the bottom of an annular groove on the nut. Formed in therotor 4 is a plurality of radially located cylinder bores I2, I3, I4,I5, I6 and H which contain reciprocable pistons I8, herein in the formof spheres or balls. The cylinder bores I2, I3 and I4 communicatethrough ports I9, and 2| with a valve'cavity 22 in the pintle 3, whilecylinder bores'l5, I6 and I1 communicate through ports 23, 24 and 25with a valve cavity 26 in the opposite side of the pintle 3. The valvecavities 22 and 26 are respectively connected by longitudinal ducts 27and 28 in the pintle 3 with ducts 23 and 3|! formed in the casing I, andthese ducts are provided with external connections 3| and 32respectively at the bottom and top of the casing, as shown in Fig. 1,and 'either'of which may be used as an inlet or outlet, as conditions ofoperations may demand;

Whenone of the external connections 3|, 32 is connected to a source ofliquid under pressure, the other'connection leads to a suitable point ofdischarge or pressure utilization. The portion of the'pi ntle 3whichextends within a bore 33 in the rotor forms a valve, as shown in Fig. 2,and serves, as shown in Fig. 1, to separate the longitudinal ducts 21and 28, thus'preventing the flow of pressure therebetween. In thisinstance, the cam track 5 is formed on the inner race 35 of aconventional anti-friction bearing, "herein preferably a roller bearinghaving rollers 36 acting against an outer race 31 which is secured'in.

a bore 38 formed in the casing l and is held in position in the bore bythe cover plate 2 which is threadedly secured at 39 within the casing.The

bore '38 is formed eccentrically with respect to the'pintle 3and therotor 4, thus causing an'off-I set relation between the axis of therotor 4an'd' that of the cam track 5. The .pintle'3 is secured to thecasing I by means of bolts or screws40, U

andan effective pressure seal is formed'between the casing and thepintle by means of a tapered fit at 4|. A gasket 42 is interposedbetween a shoulder on the casing and the coverplate 2 to provide apressure tight joint. Any leakage of fluid past the pistons and pintlemay gather in a chamber 43 in the casing, and leakage of fluid from thischamber 43 from the casing is prevented by; the seal 9, which sealingengages the casing-bore and the exterior of a shaft 44, hereinpreferably formed integral with the rotor 4. Howevergthe fluid leakinginto the chamber 43 may be vented from the chamber through passages 45and past ball check valve 46 into duct 29 or'33', depending on whichhappens to be the low pressure'or'inlet side. Pin-5J4! in plugs 48 areprovided for the retention of the valveballs in their operatingpositions. The shaft 44 projects outwardly through the nut 8 and isadapted to have connectionat 43 with either driving or driven means,depending upon whether the mechanism is being utilized as a pressuregen.-

erator or a motor.-

In order to use thehydraulic mechanism, as

of pressure supply and the connection 32 would be the discharge point.The fluid medium employed in the'mechanism should preferably be a lightlubricating oil. In operation, the centrifugal forces arising out ofrotor rotation causes the ball-like pistons, as well as the fluid in therotor cavities, to move outwardly, and, obviously, the higher the speedof rotation of the rotor, the greater the centrifugal force becomes. Asa result of this fact, the mechanism may be operated at unusually highspeeds without the danger of causing voids in the fluid cavities.Secondary priming pumps are commonly used with other known mechanisms,the function of which is either or both that of forcing the pistons outfor high speed operation and for causing complete filling of thecylinder cavities through the maintenance of pressure on the intakeside. Such known mechanisms are not only excessively complicated butresult in additional power losses. In the present mechanism, the need ofsuch auxiliary devices i eliminated by taking full advantage of thecentrifugal force arising out of the rotor rotation as a mens forthrowing the pistons outwardly as the rotor rotates and the securementof complete cylinder filling.

Following the operation of the mechanism further as a pressure generatorby referring to Fig. 2, it will be noted that clockwise rotation of therotor 4 will cause the three lower pistons to move outwardly against thecam track 5. Fluid entering the valve cavity 22 through intake duct 21would, through movement of the three lower pistons, be caused to enterthe cylinder bores I2, I3 and I4 through ports I3, 20 and 2|respectively. It will further be noted that the filling of each cylinderbore begins as the port thereof passes the cut-off section at the righthand side of the valve 34 and ends with the port passing over a similarcut-off section provided at the opposite side of the valve 34.

The valve 34 straddles the axes of the cam track 5, thus causing thefluid contained in the cylinder bores I 5, It and. I! to be dischargedtherefrom, even against great pressure, if necessary, through ports 23,24 and 25 into valve cavity 26, from whence it is conducted to the pointI of utilization through ducts 23 and 3|1'and discharge connection 32.Obviously, counterclockwise rotation of the rotor, as viewed in Fig. 2,will produce like results except with fluid flow in the oppositedirection, in which case the connection 32 would become the intake andthe connection 3|- the discharge point. It is further obvious that iffluid under pressure were introduced to the mechanism through connection3|, clockwise rotation of the rotor as viewed in Fig. 2, would streetsnot only free to roll on'the cam track E'butalso the cam track is freeto rotate with-the inner bearing race 35 on the rollers 35 arrangedbetween the inner and outer races of the bearing, thus-minimizingfrictional resistance of rotor movement resulting in improved mechanicalchi"- ciency. Furthermore, the freedom of the cam track to move with theball-like pistons miz'es ball rotation and, consequently, reduces pistonWear and the resulting leakage between the pistons-and the wallsof thecylinder bores.

In Figs. 3, 4 and 5, a slight modification'of'the structure shown inFigs. 1 and 2 is disclosed, in that the cam track bore is enlarged andarranged to'permit a cam track 52 to move laterally toand fro across theaxis of a rotor 53 for the purposes of manually regulating thevolumetric displacement and the direction of fluid flow when themechanism is employed as a hydraulicp'ressu'r'e generator and theregulation of speedand directionof rotation when the mechanism isoperated as a hydraulic motor. As in the embodiment above described, thecam track is supported by the inner raceway of an anti-friction bearingand the structure of the cylinders and pistons and the fluiddistributing valve mechanism are similar to those above described withthe'exception that there are eight cylinder bores in the rotor whichcontain eight ball-shaped pistons [8. The outer raceway of theanti-friction bearing supporting the cam track is herein supported atits top and bottom by hardened inserts or buttons 54 and 55 carried bythe casing. These buttons are preferably of hardened steel and arereadily replaceable in case of wear, and are employed to overcomeexcessive wear of the walls of the bore of the casing at the pointswhere the shiftable cam track has contact therewith. A still addedadvantage of this construction is that it permits all'of the portions ofthe casing to be brought into alinement with one setting of the parts.Lateral movement of the cam track is accomplished by a manually operablecontrol device shown in Figs. 4 and 5, comprising cylinders 55 and '1which are connected by conduits 58 and 53 to cylinders 60 and 6| securedto the casing of the mechanism (see Fig. 3). The cylinders 56 and 57contain reciprocable pistons 62 and 63 while the cylinders 60 and 5!contain reciprocable pistons 84 and 65. These cylinders and conduits arefilled with a fluid medium, preferably a light lubricating oil, throughfilling and purging plugs 66, 61, 68 and 69 which are preferablyconventional high pressure oil fittings. A conventional high pressureoil gun, such as is used for automobile lubrication, may be used forfilling the fluid system. All air should be purged from the system bydepressing the ball valve of the fitting at the opposite end of thesystem, from where oil is being pumped until air ceases to flow past thedepressed ball. After the system is completely purged, it should beunder sufficient hydraulic pressure to cause the desired solidity of thehydraulic column necessary for responsiveness of movement between theactuating cylinders 58 and 51 of the control device of Fig. i and thecorresponding actuated pistons of the cylinders 8t and iii of Fig. 3. Asthe aforementioned hydraulic column is being established, the systemshould be adjusted to cause the axis of the cam track 52 to coincidewith the axis of the rotor 5-3 and a pointer 16 on a control arm H torest at zero on an indicating segment i2. 'Ilie pointer il is famed onteen side of the base of a-sleeve 13 secured to the control arm'andarranged to be locked in any pqsrtion by being clamped tothe'indidatingsegments' by means of a threade'd'knob 'l'l'atthe'uppe'rjend of the control arm, such locking being effectedbyscrewing down the knob on the threaded end "15 of the control arm. Itwill thus be made "clear that actuation ofth'e pistons 52 and'BS of'thecontrol device of Fig. 4 causes a corresponding movement of thepistonsfi l an as which bear against the outer member 16 of theanti-meets bearing which supports the cam track 52. It is furtherobvious that the cam track 52' can thereby be laterally moved within thecasing chamber 11 to or fro across the axis of member 53 for the purposeof varying the volumetric dis placement of the rotor at any desiredamount between that of zero and a maximum. such movement will cause areversal or fluid new with a given direction of rotor rotation or'areversal of rotor rotation with a given direction of fluid flow, thusyielding complete control of theopera tion of the mechanism whether usedass fluid pressure generator or as a mechanism for the conversion offluid pressure into rotary motion.

In Figs. 6 and 7 there is shown anothermodiiication, wherein two of thehydraulic mechanisms, generally designated BI] and 8| respectively, beremotely connected by a closed nydrauuc'nqie circuit for use as a powert'ransinittiflg'inedium. The internal construction of this mechanism mayembody constant displacement featurs'sir'r iilar to those of themechanism shown in Figs. and 2 01f the variable displacementcharacteristic s similar to those shown in Fig. 3 and provided withmanual control means imilar to that shown in Figs. land 5, or thecombined manual and'autcinauc control means of certain of theothereinbodiments of the invention to be later described. In this novelarrangement, either of the units and 8| may be used as the driveno'rdrivirig'mechanism, so'long as a tank 82 is connected to the intakeside of the driven unit. Assuming the'unit B0 in Fig. 6 to be the drivenunit, and rotation is imparted to its rotor'4 by means of an outsidesource of power in one direction; the car n track 5', which maycorrespond to the cemfeac r shown in Fig. 3, would be moved laterally-inone direction, thus causing ducts 8'3and84 in a valve pintle 85, similarto the pintle 3 shown in Fig.1, respectively to become the fluid intakeand discharge. In the case of reverse rotation, movement of the camtrack 5 laterally in the opposite direction would'caiise the duct 84 tobecome the fluid intake and the duct 83 the fluid discharge. Theflexibility of the variable displace; ment feature of the constructionshown in Fig. 3 in connection with a pressure generator is thusindicated. With the mechanism shown in Fig.-6 operating a a pressuregenerator, it will be noted that fluid under pressure will be suppliedthrough an external pressure conduit 86 to an internal pressure duct 81of the mechanism 8| shown in Fig. 7, and then the latter mechanism willfunction to convert the fluid pressure generated by the mechanism 80(Fig. 6) into rotary motion to be transmitted throughits output shaft 88to-per form useful Work. The speed of rotation'of the output shaft willdepend upon the displacement of both units 80 and 8| or either that ofthe pres sure generating unit 80 or that of the output unit 8] while thedirection of rotation of the output shaft 88 is dependent upon whichside'of the "axis of the rotor 99 (Fig. 7), the cam track 90,

9 which is similar to the cam track shown in Fig. 3, is moved to. Forinstance, as the cam track 90 is moved laterally in one direction to oneside of the rotor axis, the rotation of the output shaft 88 would be inone direction, and likewise movement of the cam track to the oppositeside of the rotor axis wouldresult in reverse rotation of the outputshaft. In either case, and regardless of the direction of rotation,cylinder filling would take place during the lower half revolution, andcylinder discharge would take place during the top half revolution inthe manner described above in regard to the embodiment shown in Fig. 2,

through an internal duct 9I (Fig. '7) from where it would be conductedto the tank 82 through external conduit 92. As has been previouslystated, the power transmission arrangement shown in Figs. 6 and 7operates on a closed pressure system in connection with which the tank82 functions as both a reservoir for the oil forming the hydraulicmedium and as an air chamber. The size of the tank 82 is dependent uponthe amount of fluid pressure generated as a result of operation', but inthe present instance, is intended only for light loads and infrequentoperation, and when the mechanism is employed for heavier service, acooling system, such as will be herein later described, can besubstituted for this tank. The hydraulic fluid system should becompletely filled except for a small cavity at the top of the tank 82which should be provided for air space and'expasion of the 'oil as theresult of the 'increased temperature which can be expected to arise outof operation. For operation at relatively high speed, it has been foundbeneficial from the standpoint of cylinder filling, particularly asregarding the pressure generator or pumping end (Fig. 6), to apply airpressure on top of the oil in the tank 82. An air pump 93 is providedfor that purpose and is of the type commonly used forpumping air intoblow torches and pneumatic tires. The air cushion thus provided underpres-' sure, resting upon the hydraulic oil column, tends to solidifythe oil column conducive to complete cylinder filling permitting the useof smaller conduits and also serves to absorb any vibration and'shock'scommon to the hydraulic-fluid column of 7 all similar mechanisms.

Since one of the principal objects of the invention is the securement ofmaximum power with a minimum of'weight, high speed of operation isobviously thegreatest contributing factor thereto. It hasheretofore'been necessary to operate previous mechanisms of'the present type atrelatively low speeds, and the chief reason for such low speed operationin previous mechanisms, aside from balancing difiiculties, ha beenincomplete cylinder filling. To overcome this, auxiliary pumps have beencommonly used to supply fluid under pressure to the intake side of suchpressure generators or pumps. Such a system, while effective for thepurpose, has the disadvantages of increased weight, additionalcomplications to what is usually an already com plicated mechanism, andgreater mechanical losses. In order to insure complete cylinder fillingat extremely high speed operation, in addition to the air pressureloaded hydraulic oil column, there is provided a scavenger pump locatedin the interior of the rotor. The function of the scavenger pump is toeliminate resistance to the outward movement of the ball-like pistons bythe filling of the casing chamber 94 (Fig. 6) with fluid as the resultof internal leakage. The scavenger pump consists of a'piston 95reciprocably mounted in a cylinder 90 formed internally of the 10 shaftextension 91 of the rotor 4. The piston 95 is provided with a radiallydisposed cam track 98 which engages a pin 99 secured to the rotor 4'.The piston 95 is provided with a cross slot I00 at the end thereofopposite from the cam track 98, and this slot I00 engages arectangular-shaped extension IOI formed on the inner end of the valvepintle 85. The cross slot I00, coacting with the rectangular-shapedextension IOI of the pintle 85, while preventing rotation of the piston95 in the cylinder 96, permits longitudinal movement of the piston,thereby causing the piston to move back and forth in the cylinder as aresult of the cam track 98 engaging the pin 99 as the rotor 4 revolves.As the piston 95 moves axially outwardly of the cylinder 96, a partialvacuum is created at its inner end, causing any oil that has accumulatedin excess amount in the casing chamber 94 to flow into the cylinder 96through a port I03 in the shaft s1. Upon the return on inward stroke ofthe piston 95, the oil is trapped in the cylinder 96 through the closingof a valve I04 and dischargesthrough a valve I05 int-o the cross slotI00, from where it is free to flow into the intake duct 84 by reason ofthe rectangular extension IOI being less in width than the cross slotI00. A similar scavenger pump, generally designated I06, is provided inthe output unit 8| for removing excess oil leakage from the casingchamber I01. The structural features of these scavenger pumps areillustrated on an enlarged scale in Fig. 8. In operation, thesescavenger pumps serve to maintain a partial vacuum in the casing chamber94 and I01, thus assisting in effecting outward movement of theball-like pistons and greatly contributing to the complete filling ofthe cylinders at high speed operation. Furthermore, it is a'well knownfact that great heat arises out of the high speed operationof suchmechanisms with the casing chambers. completely filled with oil.Therefore, the scavenger pumps perform a very useful purpose, regardlessof whether the mechanism is used as a pressure generator or a pressuremotor by removing internal leakage as it occurs without the use ofpending upon demand requirements. In this con--' struction, the twounits are arranged in adjacency with the tank 82, mounted directly atthe tops thereof. The ducts 84 and 81, in this construction, arecombined into a single duct I09 in the common pintle I08, while theducts 83' and 9| are both formed in the common pintle I08 and areconnected through passages H0 and III, respectively formed in thecasings of the units and. communicating directly with the tank 82. Thescavenger pum of the pressure generator unit 68' has its piston 95'connected directly witha rectangular extension IOI' to the adjacent endof the common pintle I08, while the pistonof the scavenger pump I06 issimilarly connected with the opposite end of the pintle. Otherwise, thisunitary mechanism embodies the same features of construction andprinciples of operation as have been heretofore described in connectionwith l 1 Figs. 1, 2 and 3 and more particularly withFigs. 6 and 7.

In the modified embodiment of the invention shown in Figs. 9, and 11,there is provided an improved system of controls for the regulation ofthe speed and displacement of the pressure generator and outputmechanisms. These controls differ somewhat from the control meansprovided for manual operation and disclosed in Figs. 3, 4 and 5 in thatthey are attached to and form an integral part of each mechanism, agenerally designated H5 and H6 in. Fig. .11. They consist, in the main,of spring loaded pressure responsive devices acting against oppositesides of the. cam

track52, which is similar to the cam track shown 1 in Fig. 3, for thepurpose of automatically controlling the volumetric output of pressuregeneration and the speedof the pressure motor withinthe desired ranges.Provisions are also made for the manual adjustment of thesecharacteristics where constant volumes and speeds are desired; Byreferring to Fig. ,11, it will be seen that the spring loaded device H5consists of a spring II I enclosed within a plunger lit for operationwithin a cylinder I I9 attached to the casing I29 of the output unit.The spring II'I urges the plunger IIB inwardly and serves to exert apredetermined pressure through the plunger H3 against the outer race I2lof a cam track bearing I22; and plunger H8 is forced outwardly, as

the spring pressure isovercome, by pressure acting against the oppositeside of the camtrack. The outer end of the spring I I I bears againstthe headoi a pin I23. At the opposite side of the mechanism is thespringloaded device '8, arranged to counteract the spring pressure of theopposed device I I5 just described, and comprises a piston I24 arrangedfor longitudinal movement in a cylinder I25 and which exerts itspressure against the outer race I2I of the cam track hearing at the sidethereof opposite from the plunger 8.. The cylinder I25 is connected tothe pressure duct of the mechanism througha valve I25, conduit I2! shownin Fig. 9, and connection I28 shown in Fig. 8. The piston I24'thereforebecomes responsive to whatever pressure exists in the fluid column. Fig.11 depicts the motor or output end of a power transmission and, asshown, indicates operation at maximum piston stroke, a conditionyielding maximum torque and minimunr. speed ofrotationior a given fluidinput. Obviously, as the load imposed on the mechanism is reduced,the'pressure is reduced on the piston I24 under which condition thespring II'I reacts to move the cam track 52' toward the axis of therotor I29, thus shortening the piston stroke and increasing the rotorspeed. The foregoing assumes a constant fluid input; however, the samecontrol devices shown in Fig. 11 may be applied inreverse order to thepressure generator. end of the power unit tolikewise act, except in thereverse order, to decrease the volumetric displace.- ment of thegenerator as the result of increased pressure on. the control piston. Inother words, the control devices are interchangeable with each other forthe purpose of coordinating the direction of fluid flow with thedirection of-desired rotation, and are also interchangeable betweenunits to permit of wide variations of speed. of the output shaft withthat of the input shaft by an infinite number of steps between that ofzero and that of high overdrive, all of which is automatically regulatedso as to avoid output demands exceeding or overloading thedrivingmediurncoh nected to the input shaft.

In addition to the. aioredescribedautomatic controls, there is alsoprovided means for efiecting manual control whereby the cam tracks. ofthe mechanism may be-movcd to and locked in any desired position ofadjustment for effecting control of the volumetric displacement, thedirection of fluid flow of the pressure generator and the direction ofspeed of rotation of the output shaft. This improved manual controlvconsistsof a threaded stem or screw I36 threaded within a plug. I3-Iattached to the springcylinder I land which is arranged to be adjustedagainst the spring pin I 23 as by a knob I32 secured to the stem. Thecontrol device H6, at the opposite side ofthe. cam track, includes athreaded stem or screw ,I33 whichis threaded within a plug- I34 attachedto the cylinder I25, and this stem-is arranged, to be. screwed inwardlyand bear against the stem of the piston I24 as by a knob I35 screwed tothe stem. Obviously, by screwing the stem I30-of theicontrol device II5inwardly, the outerrace I21 of. the cam track can be caused to move.across the axis of the rotor 129 to the opposite side of thecam-track-bore I35, thereby resulting in opposite rotation of the rotor.It is further obvious that the cam track may be locked in anyintermediate position of adjustment as the result of being firmlyclamped between the screws I30 and I33. It is further obvious that themanual adjustment may be used in combination with the aforedescribedautomatic ill controls as a means'for limiting the range of antomaticcontrol in either or both the input or output ends of the mechanism asmay become desirable under certain operating requirements. It isalsoclear that in thexsimple system'of control provided, a standardmechanism may be caused tooperate so'that the input'end' has .a constantdisplacement while the output end is automatically variable or viceversa,,or both ends: may

have either constant or variable displacement as may be-desired.In-order' to make-displace= ment adjustments accurately, there areprovided pointers. I 3'I'attached to the control cylinders andindicating on micrometer graduations- I 38 onxthe operating knobs whichindicate by an infinite number of steps the exact percentage ofdisplacement delivered. by a given setting of the indicator.

In the modified embodiment shown in Figs. 12 andv 13, there is shown aunitary hydraulic power transmission, generally similar to that shown inFig. 8,.and including provisions for cooling the oil column.This'embodiment includes the same general means for manual andautomaticcontrol, as-has been heretofore described in connection withFigs. 9, l0 and 11. In Fig. 12 it will be noted that. both the input andoutputmechanisms are enclosed within a single casing I40 in lieu of theseparate casingsshown in Fig. 8, and this single. casing is closed atits ends by heads MI and I42 which may be interchangeable with eachother. This feature of interchangeability may also apply to all otherparts forming the mechanism; thus contributing much to the lowering oithecost of productionand simplification of assembly and "repair; Sinceboth ends of the mechanism are duplicates, either end. may be connectedto the driving medium'and either end may be the pressure generator endwhile the other end may be the output end. As in the embodiment'shown inFig. 8, there is a common pintle. l43zconnectedbetween the rotors of thetwo. units. Forpurposes: of explanation, it will be. assumed" that thedriving medium, as for 13 example a driving motor, is connected to acoupling I44. In this case, a duct I45 in the pintle may be the fluidinlet to the pressure generator, and the duct I46 in the pintle may bethe fluid discharge. The duct I46 extends through the valve pintle I43to the motor end of the mecha nism, thereby causing the pressure of thegenerator or input end to act directly against the ball-like pistons ofthe motor or output end, and thus imparting motion thereto and with themotor end discharging its fluid back into the duct I45. The duct I45 hasa partition I41 inserted in a conduit I48 and intersecting the duct I45centrally to block the latter so as to cause the fluid discharged fromthe motor into the duct I45 at one side of the partition to rise upalong one side of the conduit I48 into the improved cooling systemgenerally designated I49, herein mounted at the top of the casing of themechanism; and the fluid returns after cooling down the opposite side ofthe conduit I48 into the duct I45 at the opposite side of the partitionto the intake of the pressure generator. The cooling system I49 consistsof a radiator I50 and a fan II carried by a shaft I52 and provided witha pulley I53 and a driving belt I54 arranged to be driven by a pulleyI55 integral with the coupling I44. The radiator I50 has cavities I56and I51 formed in and extending crosswise of the radiator base. Thecavities I56 and I51 connect at the centers thereof with the conduit I48but .are separated from each other by the partition I41. Another cavityI58 is formed across the top of the radiator I50. Two sets of verticalradiator tubes are provided to complete the fluid circuit through theradiator; one set of which, as indicated at I59, connects between cavityI56 at the base of the radiator and the cavity I58 at the top thereof,and the other set of tubes I69 connects between the top cavity I50 andthe bottom cavity I51. A pump I6I is provided in the top cavity I 58 forthe purposes of applying the necessaryair pressure to the oil column tocause cylinder filling on the generator side under conditions of highspeed operation. A pressure gauge I62 is provided to permit theestablishment of the desired pressure and to indicate any changethereof. A filling cap I63 is provided for convenience in charging thehydraulic fluid column of the mechanism. The system should be preferablycharged with liquid to approximately the top of the pump I6I and theremainder ofthe radiator cavity I58 be left as an air chamber. Themodifications disclosed in Figs. 3 to 13 inclusive are being claimed inmy divisional application Serial No. 310,589, filed September 20, 1952.

1 Figs. 14 and disclose still another embodiment of the invention. Inthis embodiment, the hydraulic mechanism is shown applied for thepropulsion of a traction wheel and more particularly to a traction'wheelof a vehicle of the automotive type. As shown, a casing I65 may besecured to a suitable support, such as an automotiv chassis, by means ofpins and bolts fitted to cavities I66, I66 in the casing. The casing I65is also fitted with elements of construction generally similar to thosewhich appear in several of the embodiments of the invention heretoforedescribed, namely: a cover I61, a pintle I66, a rotor I69 and a camtrack I10. The rotor, as in the preceding embodiments, has radiallylocated cylinder bores containing reciprocabl pistons of spherical orball shape, and the-cam track is supported by the inner race of ananti-friction 14 bearing against which. the pistons react. The rotor I69has attached to its outwardly extending spindle portion IN, a flange I12and the latter is secured to the spindle portion by a conical gland I13which is held in wedged relation between the spindle portion and theflange as by cap screws I14 spaced at intervals around the face of thegland. A brake drum I15 is secured to the inner surface ofthe flange I12as by the riveted ends of studs I16, while a wheel flange I11 is securedto the outer face of the flange I12 as by nuts I18 fitted to theoutwardly extending threaded portions of the studs I16. A tire rim I19supporting a conventional pneumatic tire I is secured to the wheelflange I11 as by spot welding or by any of the conventional rim lookingdevices in common use. A brake band I8I is secured in place within thebrake drum by means of an anchor member $83 attached to a lug I84 as bybolts I85. A hydraulic brake operating cylinder I86, arranged betweenthe ends of the brake band for the expansion thereof, is secured to 2.lug I81 as by bolts I68. The Wheel motor mechanism herein disclosed isprovided with spring loaded pressure responsive devices for the purposesof varying the displacement and, consequently, the torque delivered bythe mechanism in accordance with the demands of the conditions ofoperation. To achieve this, connections are made between an inlet I89 ofa pressure cylinder I90 and the pressure side of a pressure generator,as, for example, a pressure generator of the kind shown in Figs. 6 and8. The cylinder I90 is arranged in a vertical position and is secured tothe top of the motor casing I65 and contains a piston I9I which engagesthe outer race I92 of the anti-friction bearing which supports the camtrack I10. A vertical cylinder I99 is secured to the bottom of thecasing and contains a plunger I94 which is yieldingly held in engagementwith the outer bearing race by a coil spring I95 enclosed in thecylinder. Obviously, as the pressure required to impart motion to thewheel motor increases, the piston I9I in the cylinder I90 acts to movethe cam track I10 a greater distance from the axis of the rotor I69, theextent of movement depending upon the reaction to such movement set upby the spring I95 of the plunger I 94 located opposite from the pistonI9I. The efiect of such cam track movement would be to increase thepiston stroke with a corresponding increase in the turning torque of themechanism and a reduction in the speed of rotation. Likewise, areduction in pressure will result in shortening of the piston stroke andincreased speed of rotation, and at no pressure the spring I95 may becaused to return the cam track I10 to where its axis coincides to thatof the rotor I69 under which circumstances a condition of free wheelingexists. Normally, during wheel rotation, the cam track is eccentricallydisposed with respect to the axis of wheel rotation, and under thiscondition, the rate of wheel rotation may be controlled by reversal offluid flow through the motor, under which condition it may be caused tofunction as a pump and then serves as a means for resistingwheelrota-tion. Obviously, the movement of the vehicle may also becontrolled by the braking provisions described above. Any of thepreviously described mechanisms of th other embodiments may be employedfor supplying fluid under pressure to the wheel motor mechanism, butpreferably the pressure generator should be provided with a coolingsystem such as shown in Figs. 12 and 13, scavenger pumps such as shownin Figs.

Sand 8, and a suitable system such as shown in Figs. 4, 5, 6 and '7 forvarying the displacement thereof as an auxiliary means for controllingspeed and the rate of doing work so as to conform closely to th maximumpower of the driving motor. The driving motor for the pressur generatorunder such conditions may operate at constant speed, a condition veryfavorable to the use of a diesel-type engine as a driving medium for theautomotive vehicle. This embodiment is being claimed in my divisionalapplication Serial No. 202,372,. filed December 22, i950.

In Figs. 16 and 17 ther is shown a modified form of hydraulic motormechanism for the propulsion of a traction wheel. In this construction,the hydraulic mechanism embodies a compound hydraulic wheel drivingmotor which is generally similar in design to certain of the embodimentsabove described and similarly consists of a casing I91 which may besecured, as by bolts 198, to a suitable support I99, such as anautomotive chassis. Lik the form shown in Figs. 14 and 15, the casing isfitted with elements of construction similar to those of several of thepreceding embodiments, namely: a cover 5598, a valve 201, a rotor 2G2,and cam tracks. The rotor, in this instance, has two series of radiallylocated cylinder bores arranged side by side and containing reciprocableball-like pistons engaging cam tracks 2% and 2&4 supported by the innerraces of anti-friction bearings and against which the pistons react inth manner previously described. The rotor has attached to its outwardlyextend.- ing spindle portion 2%, a flange 2&5 secured to the spindleportion bya conical gland 28"! which is held in wedged relation betweenthe spindle portion and the flange 266 as by cap screws 263 in themanner similar to the form described above in connection with Figs. 14and 15. A wheel flange 269 is secured to the flange 266 as by welding orotherwise. A tire rim 2W supporting a tire 2H may be secured to thewheel flange 209 as by spot welding or otherwise. The rotor 2&2 isherein journaled on ball bearings 2H! and 213, respectively supported bythe casing end wall 2M and the cover 200, and, in this instance, thevalve pintle corresponding to the pintle E63 of Fig. 14 is omitted. Acylindric member corresponding to the valve pintle, is supportedcentrally within the rotor and has tubelilae projections Z56 fitted inpacked recesses in the casing end wall, and ducts Zil and 253 in themember 2 l5 extend inwardly through the proiections 258 intocommunication with passages 2 i9 and 226 in the casing end wall andconnected respectively to a pressure source and a pressure discharge.The member 2 I5 is formed with suitable fluid distributing grooves andthe valve 26!, which is of the sleve type, and is secured to the rotorand surrounds the member H5 and has ports for distributing fluid underpressure to and exhausting fluid from the cylinder bores of the rotor toeifect recipocation of the pistons. As in the embodiment shown in Fig.1, valve controlled passages are provided for preventing excessivepressure due to leakage from building up in the casing chamber. Theouter races 22| of the antifriction bearings supporting the cam tracks263 and 284- are supported within a shiftable annulus 2'22 which isguided at its sides in the cam track chamber of the casing by steelinserts 223 secured as by screws 224 to th casing side walls. As in theembodiment shown in Figs. 14 and 15, the wheel motor mechanism isprovided with spring loaded pressure responsive devices for i6 varyingthe displacement and, consequently, the torque delivered by themechanism in accordance with the demands of the conditions of operation.To accomplish this, connections are made between th inlet 225 of a pairof pressure cylinders 226 and the pressure side of the pressuregenerator.- These cylinders are secured in a vertical position at thetop of the casing and contain reciprocable pistons Z'Z'i which bearagainst" the upper side of the cam track annulus 222. Positioned byscrews 228 within the cam track chamber at the bottom of the casing is aspring 229 which acts on the bottom of the cam track annulus to opposethe pressure exerted thereon by th pressure piston 22?. Obviously, asthe pressure required to impart motion to the wheel motor increases, thepistons 221 in the cylinders EEiiac-t to move-the cam tracks 26% and 264a greater distance from the axis of the rotor EilE, the extent ofmovement depending upon the reaction to such movement set up by thespring 22% in opposition to the pistons. The eiiect of such cam trackmovement would b to increase the piston stroke in themanner of theembodiment above described in connection with Figs. 14 and 15 with acorresponding increase in the turning torque of the mechanism andreduction in the speed of rotation. Likewise, a reduction in ressurewill result in shortening of the piston stroke and increased speed ofrotation and at no pressure the spring 229 may be caused to return thcam tracks 203; 28s to where their aXes coincide with the axis of therotor 2% under which circumstances a condition of free wheeling exists.Normally, durin wheel drive, the cam-tracks are eccentrically disposedwith respect to the axis of wheel'rotation, and under this condition,wheel rotation may be controlled by reversal of fluid flow through thereversely driven motor under which condition the motor may be caused tofunction as a pump, thereby to serve as a means for resisting or brakingwheel rotation.

In the modified embodiment shown in Figs. 18

to27 inclusive, the pressure generator or pump is of. the multi-stagetype. The closed fluid supply and cooling system is similar to thatabove" described in connection with Figs. 12 and 13, and the structureof each pump unit is similar tocertain of, the embodiments abovedescribed.

This embodiment embodies unique features and operating characteristicsnot present in the forms of the invention above described, chief ofwhich are the balanced forces within the rotor and pintl which. greatlyrelieve the bearing loads under high pressure operation andsecond-lypermits of obtaining different operating characteristics by theprovision of interchangeable pintles and by inserting the particular onerequired for the desired perfomance in the manner to be laterexplained-in connection with later embodiments. There is a casing 235having mounted therein a stationary shaft or pintle 236 generally likethe p-intles of certain of the embodiments above described and similarlyheld in place by bolts or screws. A rotor 231 arranged in thecasingchamher is journaled in bearings respectively supported by thepintle and an end closure of the casing in a manner similar to thatshown in Fig, 1. The driving medium, as for example, a driving motor, isconnected to a coupling M4 secured to an input shaft 238 intergral withthe rotor. The rotor, in this instance, has four series of radiallylocated cylinder bores arranged sideby side longitudinally of the rotorin parallel transverse planes and containing reciprocable

